The present invention relates to a device for connection within a telephone circuit, particularly a multiparty telephone circuit, to permit the central office to determine which party is making an outgoing phone call for billing purposes.
In multiparty telephone systems, the central office must be able to determine which party is making an outgoing call in order to properly bill that party. In the past, the telephone company provided one party of a two party line with a phone that would produce a special signal that could be detected by the central office when that party placed his phone off hook. Each party's phone is branched off the tip and ring line of the telephone system. Generally, one party is designated the tip party and the other party is designated the ring party. A tip party identifier was provided by giving the tip party of the two party system a telephone specially designed to produce an identifying signal at the central office when that phone is off hook. When one party takes their phone off hook to make a call, the central office would test for this signal and if the signal was seen they would know that the tip party was making the call and if that signal was not seen, the central office would know that the ring party was making the call.
In the present deregulated environment, it is now mandatory that the customer be able to buy and own his own equipment by going to any FCC approved manufacturer or supplier for the phone. Thus, there is a need for a separate device to be connected within one party's telephone loop in order to produce a signal that can be detected by the central office when that party's phone is off hook. The device must be able to detect when the phone is off hook and produce the identifying signal only when the central office is testing for that signal.